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From:   Konstantin Aladyshev <aladyshev22@gmail.com>
Cc:     gregkh@linuxfoundation.org, benjamin.tissoires@redhat.com,
        aladyshev22@gmail.com, ivan.orlov0322@gmail.com,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        john@keeping.me.uk, lee@kernel.org
Subject: [PATCH 1/1] usb: gadget: f_hid: fix report descriptor allocation
Date:   Tue,  5 Dec 2023 11:54:03 +0300
Message-Id: <20231205085404.175-2-aladyshev22@gmail.com>
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The commit "usb: gadget: f_hid: fix f_hidg lifetime vs cdev"
(89ff3dfac604614287ad5aad9370c3f984ea3f4b) has introduced a bug
that leads to hid device corruption after the replug operation.
Reverse device managed memory allocation for the report descriptor
to fix the issue.

Tested:
This change was tested on the AMD EthanolX CRB server with the BMC
based on the OpenBMC distribution. The BMC provides KVM functionality
via the USB gadget device:
- before: KVM page refresh results in a broken USB device,
- after: KVM page refresh works without any issues.

Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>
---
 drivers/usb/gadget/function/f_hid.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index ea85e2c701a1..3c8a9dd585c0 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -92,6 +92,7 @@ static void hidg_release(struct device *dev)
 {
 	struct f_hidg *hidg = container_of(dev, struct f_hidg, dev);
 
+	kfree(hidg->report_desc);
 	kfree(hidg->set_report_buf);
 	kfree(hidg);
 }
@@ -1287,9 +1288,9 @@ static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
 	hidg->report_length = opts->report_length;
 	hidg->report_desc_length = opts->report_desc_length;
 	if (opts->report_desc) {
-		hidg->report_desc = devm_kmemdup(&hidg->dev, opts->report_desc,
-						 opts->report_desc_length,
-						 GFP_KERNEL);
+		hidg->report_desc = kmemdup(opts->report_desc,
+					    opts->report_desc_length,
+					    GFP_KERNEL);
 		if (!hidg->report_desc) {
 			ret = -ENOMEM;
 			goto err_put_device;
-- 
2.25.1